en علوم آزمایشگاهی Laboratory Sciences تحقيقي Original Paper <div style="text-align: justify;"><span style="font-family:Times New Roman;"><span style="font-size:12px;"><b>Background: </b>Smoking is recognized as a significant risk factor for cardiovascular diseases (CVD), yet its influence on blood levels of homocysteine, folic acid, and vitamin B12 is not well understood. This study aimed to explore how smoking affects these biochemical markers in patients with CVD.<br> <b>Methods:</b> The study included 88 participants diagnosed with CVD, who were categorized into smokers (n=44) and non-smokers (n=44). Serum concentrations of homocysteine, folic acid, and vitamin B12 were assessed using ELISA. Additionally, blood pressure (both systolic and diastolic) and body mass index (BMI) were recorded.<br> <b>Results:</b> Smokers showed significantly lower levels of folic acid (22.41 &plusmn; 5.95 ng/mL) compared to non-smokers (28.05 &plusmn; 4.13 ng/mL, p = 0.000). No significant differences were observed in homocysteine (p = 0.958) or vitamin B12 (p = 0.578) levels between the two groups. A negative correlation was found between folic acid and systolic blood pressure in smokers, while no significant associations were noted among folic acid, vitamin B12, and homocysteine.<br> <b>Conclusion:</b> In patients with CVD, smoking is linked to significantly lower folic acid levels, which may lead to increased systolic blood pressure. These results underscore the need to monitor folic acid levels in smokers who are at risk for cardiovascular issues.</span></span></div> Cardiovascular diseases, Blood pressure, Cigarette smoking, Folic Acid, Vitamin B12, Homocysteine 22 24 http://mlj.goums.ac.ir/browse.php?a_code=A-10-1548-1&slc_lang=en&sid=1 Saif Karim 100319475328460030510 100319475328460030510 No Metabolic Disorders Research Center, Golestan University of Medical Sciences, Gorgan, Iran Mahdi Zahedi 100319475328460030511 100319475328460030511 No Ischemic Disorders Research Center, Golestan University of Medical Sciences, Gorgan, Iran Zeinab Mohammadi 100319475328460030512 100319475328460030512 No Metabolic Disorders Research Center, Golestan University of Medical Sciences, Gorgan, Iran Nahid Poursharifi 100319475328460030513 100319475328460030513 No Metabolic Disorders Research Center, Golestan University of Medical Sciences, Gorgan, Iran Mehdi Khorami 100319475328460030514 100319475328460030514 No Metabolic Disorders Research Center, Golestan University of Medical Sciences, Gorgan, Iran Mohsen Tatar mohsentatar@ymail.com 100319475328460030515 100319475328460030515 Yes Metabolic Disorders Research Center, Golestan University of Medical Sciences, Gorgan, Iran